The Dying Heart
by ellie.dulcie-xx
Summary: When Natsu becomes the Demon END in the fight against Zeref, he becomes a monster who hurts enemies and comrades alike. With all of the members of the Fairy Tail guild injured or too far away to help, it is up to Lucy to save him. But at what price? AU. Three-shot. Nalu.
1. Chapter 1

"Natsu! Please, stop this! This isn't you!"

The sky was red, and the dying light of the moon silhouetted the battlefield that had once been the thriving city of Magnolia. The buildings had been destroyed, and the residue of magic was thick in the air. The corpses of the Alvarez army lay scattered on the ground, like crumpled flower petals, stained red with blood. Where once screams had filled the air, now the only sound that could be heard within the desolate city was the crackle of fire, as soot and ash stained the sky black, like a miasma of darkness. The air was saturated with fear, and even though the battle for Fairy Tail was over, and the dark wizard Zeref defeated, the Wizards continued to fight. The sounds of crazed laughter filled the air, as the members of the once proud guild lay broken and battered through the streets. They wished they did not have to fight, but the man who had once been their comrade could not be allowed to run wild - it would mean the end of Fiore.

Natsu Dragneel, or as he should be called now, the demon END.

He had lost control as the fighting died down. Zeref had used the book of END, and though Natsu had managed to retain some semblance of control at the beginning, there was no sign of him know. He attacked people that just a few minutes ago, he would have given his life for. He broke them, using the knowledge he had of them from being Natsu. Nats- no, END had attacked his guild mates, breaking them apart in the most cruel ways possible, laughing maniacally at their misfortune. The Demon had ripped of Jet's left leg, meaning that he would never be able to run again, to feel the wind streaming past him as he raced - deprived of the thing he loved most. Levy and Gajeel both had horrific, disfiguring burns down half of their bodies, while Levy was also missing both her eyes - long scars adorning her once beautiful face from where END had ripped them out. She would never get to read again. All of Erza's long red hair - for which she had been named - was missing, and it would never grow back, due to the deep burns that were splashed across her scalp. Juvia was missing both her arms, as they had evaporated because of the heat, and it was taking everything that Gray had to stop the rest of her from turning to gas as well. Wendy was doing everything to help her injured Guild-mates, but she could not afford to attack, after all, wind only amplifies fire, and they could not afford to give END more strength. The same applied to Macao and Romeo, who were both forced to watch as their comrades were injured and broken one after the other, unable to help because of the fire magic that they wielded. Wakaba was unconscious, huge claw marks dragged through his chest, and it was taking everything that Porlyusica had to keep him alive. The Thunder Legion lay scattered around the battlefield, unable to move even an inch. Biscow was missing his eyes, much in the same way Levy was, and would never be able to use his magic properly again, while Evergreen was left with bleeding stumps where her wings had once been. Freed was unconscious and missing his right arm, while Laxus, who had still been recovering from his earlier fights had been flung to the other side of Magnolia, his back ripped open from the impact. Reedus was missing both of his arms, and would never be able to paint or use magic again, while the three Straus siblings were buried under the rubble of the guild hall, clutched in each other's arms as they attempted to get out before they died. Cana and Gildarts were still on the other side of Magnolia, wiped out from their battle with the Wizard August, and in no position to help their Guild Mates.

The only one left was Lucy. She had been on the other side of Magnolia with the Exceeds and Yukino, when she had felt the demonic energy of the Demon END - she recognised it from the brief battle between Gray and Natsu. Lucy had ran as fast as she could in the direction she could sense it coming from, needing to help him in anyway she could.

But she had been too late.

By the time she had arrived, all of her comrades were injured and dying - missing limbs and the will to live. They had all wanted to stop the demon END, but had been unwilling to hurt Natsu's body, and Lucy felt the same.

But she knew that she had to fight.

Lucy was often viewed as one of the weaker members of the powerful Fairy Tail guild - and compared to her more combat orientated teammates, she could definitely see why. But she knew something that most people did not, and it was why she was so respected among those who understood her magic.

Celestial Magic was the hardest Magic to learn.

There had once been thousands of Celestial wizards, so it was often underestimated, but after the events with the Infinity Cloak, only two Celestial Wizards remain - Lucy and Yukino. Most people simply did not had the dedication and patience needed in order to learn the dying art, nor the motivation and magical energy. It requires insane amounts of magic to even summon a single spirit, let alone keep them in the realm of Earthland long enough to battle. So much of the Ancient Magic was forgotten, and it was only through the Heartfilia archives that Lucy knew anything at all. During the year where Fairytail was disbanded, Lucy had gone back to the Heartfilia estate, and read through all of the archives, in search of more information on Celestial Magic, in the hopes of mending Aquarius's key. However, instead of the information she had been looking for, she had learnt other, completely startling facts. She had learnt of the rich history shared between the Heartfilia family and Celestial spirits - starting with Anna all those years ago, when she had used the Twelve Zodiac keys to open the Eclipse gate, and when Layla had opened it again, using her own life force in the place of Aquarius's key. Lucy had learnt more on the Star Dress, as well as Hyper Magic - a long forgotten branch of Celestial Magic. The young blonde had also learnt about Primordial Magic, and how Celestial Magic was the closest thing to the powerful Energy, that all magic originated from. But most importantly, Lucy had learnt of the purifying nature of Celestial Magic. Her magic originated from the stars, burning balls of gas billions of miles away, with a light so powerful, that could reach through the deepest, darkest places within space. Her magic was that light, and it had the power to burn away the darkness - physical, and within the hearts of humanity.

It was that knowledge which she would use to save Natsu.

To her, Natsu was the light that burned with Fairy Tail's will, while the Demon END was the darkness of Zeref. Like the spell, Fairy Law, she would destroy what was unwanted, while leaving behind the Natsu Dragneel that she loved.

Lucy would save him, and in turn, the Fairy Tail guild.

As Gray had once said, it wouldn't be Fairy Tail without Natsu - it was simply unimaginable. Lucy wished to save her guild, but she also had to save the boy she loved, and she would do both. She would prove that she wasn't the weak little girl who worried about her looks - watching from the sidelines as her Teammates fought, waiting to be rescued. Like she had told her Father so many years ago, she was no longer Lucky Lucy Heartfilia. She was Lucy of Fairytail.

And it was time to prove it to the world.

The Celestial wizard unraveled her whip, and sent it flying towards her demonic teammate. She didn't want to hurt him - she knew that Natsu, her Natsu, was in there somewhere - but at that moment, she had very little choice. The Fleuve d'etoiles light up like a Christmas tree as it snaked towards END, before it latched onto Natsu's leg, wrapping around it. Lucy yanked with all of her strength, sending the Demon toppling towards her. END quickly righted himself, causing Lucy to lose her grip on the Fleuve d'etoiles, leaving the demon clutching onto her precious whip. Without her Celestial Magic flowing through it, it was nothing special - identical to the ordinary whip she had joined the Fairy Tail guild with. But Lucy knew better than anyone how deadly the length of leather could be in the wrong hands. And as of now, Natsu's were definitely the wrong hands. The whip arced through the air towards her, and Lucy lunged to the side, rolling out of its path. As the leather flew towards her again, the Celestial Wizard drew one of her Golden Gate keys.

"Star dress: Taurus Form!" She held the key to her chest and felt the familiar tingle of magic as it flowed over her clothes, changing them into her cow-patterned Star Dress. When she heard the familiar snap of a whip, the last Heartfilia jumped up into the air, clenching her fist as she zoomed towards the demon END. Lucy could feel the wind whipping around her head, tousling her long blonde hair. END glanced up at her and then, almost lazily, held up his hand and catching her fist. He didn't even flinch as the ground beneath him splintered and cracked. As his claws dug into her fist, Lucy flipped back, skidding across the ground as she pulled two other Zodiac Keys.

"Open, gate of the Lion, Loke!" She called out, her voice ringing through the desolate town. She heard the familiar chime of the Gate Key, as Loke shimmered into existence, his face set. "And, Star Dress, Aquarius Form!" Lucy pointed the shattered key inwards, feeling the defensive magic take hold as her clothes rippled, changing form.

"Please distract him while I cast this spell."

"You got it, Lucy."

The Celestial Mage watched as Loke attacked END - saw the sorrow in his eyes. He knew everything that she knew through the bond she shared with her Spirits - and she in turn knew how much it was hurting him to fight Natsu in this way. Out of anyone, Loke had the best idea of what she was planning - The Celestial Spirit King had made it clear that as a Demon, it would be near impossible to kill END, but that they had to do what needed to be done - no matter the cost. The Demons from the Books of Zeref were anomalies, and they could not be allowed to remain within the Realm of Earthland.

Lucy closed her eyes, feeling the familiar build up of Ethernanos as she began to incant.

 _Survey the Heavens, Open the Heavens..._

 _All the stars, far and wide..._

 _Show me thy appearance..._

 _With such shine._

 _Oh Tetrabiblos..._

 _I am the ruler of the stars..._

 _Aspect become complete..._

 _Open thy malevolent gate._

 _Oh 88 Stars of the heaven..._

 _Shine!_

 _ **Urano Metria!**_

The planets spun around her, sending huge amounts of magic flying at END. As the ancient spell hit him, the Demon let out an unearthly scream sending huge bursts of fire out from his body. The Demon's leathery wings blistered and flaked, and his long twisted horns crumbled. The fire that previously enveloped his body dissipated as the Hyper Magic swirled around the Demon, almost like electrical currents. When END finally stopped screaming, he tumbled towards the ground like a puppet without strings. Lucy ran forward, not giving the Demon time to rise. She could see the fire moving around him creating sparks and healing the wounds on Natsu's body. Good. She wanted to stop END, but it would be a cold day in hell before she wanted to hurt Natsu. Lucy released her spells, shutting Loke's gate and releasing her Star Dress, as she gathered every ounce of her magic to purify Natsu. Crossing the last couple of metres to her pink haired teammate, she arrived just as END was getting to his feet, a scowl etched into his face. She sadly smiled, as tears flowed freely from her eyes, and pressed her lips to his.

The world was silent, as Lucy kissed Natsu. She poured her Celestial Magic into him, purifying the Demon that had taken root in his body. Lucy held his face with her hands, as he stopped resisting, settling his arms around her waist. The Celestial Wizard could feel her Guildmates eyes resting on the pair, and she smiled once again, as she poured the last of her magic into Natsu, destroying END. As his demonic traits vanished, she felt an odd tingling in her body, and knew what was to come.

Lucy broke the kiss apart, looking at Natsu's perfectly human face with a smile. He blinked down at her as the glassy haze disappeared from his eyes.

"Lucy…?"

The Celestial Wizard felt herself glowing, a bright light shining out of every crevice of her body.

"I'm sorry Natsu." She whispered, smiling up at her pink haired teammate. "It looks like I have to go. I'll be the first to enjoy the next adventure though. I'll miss you, but don't come too soon, ne?"

"What are you…" Natsu was confused. The last thing that he could remember coherently was Zeref opening up the book of END - everything after that was a blur. And then, there was Lucy. Kissing him. He had wanted to kiss her for a while now - no matter how much he denied it - but the pinkette was confused at how it at happened. Glancing around, his rage bubbled up as he took in the ruins of Magnolia and the Fairy Tail guild - his injured comrades bleeding on the upturned streets. However, it wasn't until he saw Levy, with her missing eyes and horrific burns, that he realised what had happened. He had hurt his friends. Like a dam, all of his memories burst free, and he could remember ripping his comrades limb from limb. He had felt trapped - unable to do anything but watched as END, within his body, hurt those dear to him.

And then there was Lucy, who had saved him from the Demon he had become, and was now glowing. Her magic filled all of his senses, and to him, it felt as though the Celestial Mage held all of Magnolia in her arms. She drifted apart slowly, separating out into magic within his arms. And then, she flew.

Lucy laughed merrily as she felt the wind tug at her hair, as she soared through the desolate town. Everything she touched bloomed into life, as the purifying Celestial Magic she treasured reached out and touched the city. Flowers bloomed, and the grass straightened, like a tiny green army. Trees uncurled and blossomed, and as her magic touched the people, wounds knit back together, and the flow of blood stopped.

 _Purify. Heal. Grow. Love._

This was Primordial Magic, the energy that all magic was created from. Lucy could remember how Master Hades had lost himself in the search for this magic that she now claimed. How her mother had told her that One Magic was not something you fought with, it was something you grew within your heart, and then shared with the world. Only those who could face the most difficult of situations with a smile on their face could ever wield the mighty magic.

But all power came with a price.

To access Primordial Magic, Lucy had had to use all of her magic. Every. Single. Drop. And now, she was being pulled apart, her body turning into pure magical energy. And as the wind tugged her apart, she broke the contract with each of her spirits, and soared. Her consciousness separated, flowing around her comrades and sharing her memories of Fairy Tail with them, before disappearing into nothingness. And as everything that made her Lucy vanished from Earth Land, she was at peace. The Celestial Mage knew that she had protected her Nakama, and she was eternally grateful for that, and everything else that Fairy Tail had brought her. All of the good times and the bad. All the new friends she had made. The experiences she had shared with them.

Eisenwald. Galuna Island. Phantom Lord. The Tower of Heaven. The Battle of Fairy Tail. Oracion Seis. Edolas. Tenrou Island. The Infinity Cloak. Grand Magic Games. Eclipse Spirits. The Sun Village. Tartaros. Avatar. The Alvarez Empire.

So many adventures, with so many friends. But now… it was time for Lucy Heartfilia to face the next one. Alone.

Her next big adventure…

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.

.

.

.

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 **A.N.**

This is going to be a two shot about an alternate ending for the Alvarez empire arc. I hope you enjoyed this so far.

Please review if you liked this or have any comments.

Ellie.


	2. Chapter 2

Natsu loved to star gaze, now. Before, he had never really understood why people enjoyed it so much - just looking up at tiny balls of light that were millions of miles away. It wasn't like food, that you could eat and touch and interact with. They were just… there.

Now though, Natsu could truly appreciate how beautiful they were. The stars were like fireflies, pinned to a velvet canvas of inky blue, or perhaps they were more like fairy lights on New Year's Eve. Either way, they were incredible.

And yet, watching the stars twinkle was oh so bittersweet for the young dragonslayer. He could always picture Lucy lying next to him, pointing out all of the constellations in the night sky. It had been their thing to do on missions. Him, Happy and Lucy - watching the stars. Looking back, Natsu had never really listened to what Lucy had been saying, instead, watching her face as she practically glowed from the excitement. He had seen her love of her spirits and of the stars so clearly that it had been blinding.

But now she was gone. Forever.

And he had been the one to kill her.

He knew that he hadn't actually shoved a claw through her heart, but it was entirely due to his own lack of control that she was gone. If he had only been able to take control over END, then Lucy would still be alive, and his friends wouldn't be scared and broken. His guildmates would be able to look him in the eye without flinching away, and he would be able to look at them without being overwhelmed with guilt.

Maybe Natsu wouldn't be so broken, but Lucy's death had left him empty.

.

.

.

And yet,

Lucy was still sort of there.

Her magic had helped Magnolia grow after the attack of the Alvarez Empire. She was in the blooming tulips and shimmering rainbow cherry blossoms. Her magic swirled around the city and guild she had called home, watching over the town even after her death. Everyone could sense her, and everyone knew of her sacrifice.

Lucy was a hero to everyone.

But Natsu was alone.

.

So yes, Natsu loved stargazing.

It was a way to connect to the woman he loved.

 **A.N.**

 **Sorry for the huge gap between updates, but I had a serious case of writer's block. I got my inspiration on an expedition into the wilderness.**

 **Since this chapter was so short, I'll be posting another one in the next few days.**

 **Please review and tell me what you think.**

 **Sorry for the wait**

 **Ellie**


	3. Chapter 3

Levy couldn't see anymore - her eyes having been gouged from her skull. She didn't hate Natsu for what had happened to her, but there were times she wished that she could. Her life would be so much easier if she could blame everything on the dragonslayer, but even without eyes, Levy knew that he would be wallowing in guilt.

She had always known that Lucy and Natsu loved each other.

It had been plain as day.

There were times, now, when Levy could barely muster up the courage to leave her bed in the morning. Her burns would stretch taut and the place where eyes had once been would itch. Her books would almost mock her from their place on her walls, and she could almost see them towering over her.

Levy had always loved books. When she had first come to Fairy Tail - a small lonely child - they had been her only companions. And now, even they had been taken away from her. Just like her parents.

Gajeel had been the only thing helping to keep her sane. He would meet her in morning just outside the dorms, and walk her down to the guild. Then, they would sit, and he would read to her as she tried to learn Braille. Then, he would help her put a healing salve on all her burns, and they would both walk into town for lunch. They'd visit Lucy's grave and do a quick job within Magnolia, before returning to the guild, followed by the dorms. The routine helped her get on with her life, and gradually, Levy began to heal.

She made goals for herself, to help her look to the future, rather than remain stuck in the past. She wanted to go on missions again, to finally make it to S-class. She wanted to learn Braille, so that she could enjoy her books again.

But more than anything, Levy wanted to complete Lucy's novel, and her help her dead best friend finally realise her dream. Lucy and Levy had been so close, from the very moment they had met. Always talking about books and long dead languages that they had found. Later, Lucy would complain about the complete and utter destruction that her team wrought, all while smiling contently to herself. Lucy had been a beautiful burning ball of light, like the stars she so dearly loved, and had helped Levy grow and mature as a person. They had both influenced each other in so many ways, and they had both become better because of it. Everyone in the guild had eventually come to treasure Lucy because of the incredible, genuine person she had been, but Levy was proud to have been one of the first to have seen it. Even if she was after Natsu and Happy in that regard. But the relationship those three had shared had been so rich and heartfelt, that it didn't bother the young Mage at all.

So Levy was going to ensure that the novel Lucy had slaved over would be published, to help her accomplish her dream.

The first time Levy had read the novel, she had burst into tears. She hadn't known beforehand, but the novel was Lucy's autobiography - her story ready to be told to the world. The names had been changed around a bit, but all of the characters and stories were so alive and real, Levy could practically see them in her mind's eye. It was like Lucy was there, telling her about everything that had happened in her life. All the hardships she had suffered and joy that she had felt. The novel let her see a new side to her friend, and the various letters addressed to Layla at the start of every chapter practically broke her heart. Reading the words Lucy had penned for her dead mother had felt like such a private thing to do, that Levy had felt so overwhelmed. Shocked that Lucy would have left something so personal to Levy in her will.

But Levy would ensure that the book was finished. All it needed was a small note at the back, telling all the people she was sure would read it, exactly what had happened to Lucy.

How she had saved them all.

However, just as Levy reached the end of the book, she came across one final letter. It was hastily written, with none of the flowery language and thoughtful words used throughout the rest of the novel. The paper was signed and dirty, but it was the final thing that Lucy had ever wrote. Her final note, and her last confession. She spoke of love and friendship and family, and Levy knew that this note was not for her, nor for the book.

Perhaps within the next few days, the note would be found upon the doorstep of a dragonslayer's home. Left for the man her best friend had loved so much.

.

.

Levy had lost many, many things in the past few months. Her eyesight. Her books. Her best friend. But she knew that things could be so much worse.

After all, even with all that she had been through, there was still a new life, growing inside of her.

Perhaps they would name her Lucy.

 **A.N.**

 **And this is the final chapter.**

 **And there wasn't even a long wait!**

 **I love Levy so much, and feel like her friendship with Lucy is serious underrated - often pushed to the wayside in favour of romance.**

 **In terms of interests, I'm a lot like Levy, so this was fun to write, and I hope you all enjoy.**

 **Please review and tell me what you think.**

 **Ellie**


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